The ubiquity of Internet connectivity and the unprecedented growth in network access bandwidth have been fueling the demand for more versatile forms of on-line content. Currently, video is one of the most bandwidth-demanding forms of on-line content. Traditionally, video is broadcast over cable programming networks and successful delivery of high-quality video over an Internet connection is subject to several service constraints. Recent technologies, such as ADSL, VDSL, direct Ethernet connection, and WLAN, have largely removed the access bandwidth bottleneck. Server overloading and network congestion, however, can still pose potential service constraints.
Peer-to-peer overlay (P2P) networks have attracted growing interest as one solution to delivering video content. A P2P network operates over a conventional network-layer infrastructure, such as the Internet, and peer nodes are “aware” of the states of other peer nodes. Content delivery is not undertaken by one particular server. Instead, a group of peer nodes directly exchange data or services among themselves. Thus, P2P networks provide a favorable environment for delivering streaming data, such as video, because server overloading is avoided and network congestion is reduced. P2P networks also scale gracefully as the number of users increases.
The successful operation of a P2P network partly depends upon user participation, which is often a function of user satisfaction and quality of service, or QoS. Conventionally, network operators can provide guaranteed QoS using dedicated, tightly-controlled, and over-provisioned network resources, which increases service costs. Customers are required to pay a premium flat fee for high QoS regardless of the amount of the services consumed. For example, a user can be required to pay a flat monthly fee for a 1.5 Mbps leased line service, although the actual service used by the user can vary from month to month. Furthermore, even if the user experiences temporary service degradation, the service provider often charges the same fee.
Additionally, providing guaranteed QoS in a P2P network under the same approach is neither practical nor economical. The advantages of P2P networks are largely attributable to the distributed nature of the architecture, under which central control and network resource allocation are incompatible. In a P2P network, QoS can vary based on a user's location, network condition, and time of service, and a flat fee structure could significantly lower user satisfaction, thereby discouraging user participation.
Hence, a need arises for a dynamic billing system that is based on actually delivered QoS in a P2P network.